Rutile

Oxide mineral composed of titanium dioxide

Rutile is an oxide mineral composed of titanium dioxide (TiO2), and is the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion.

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